Mention default values for readwrite=/ioengine=/mem= in documentation

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 9ed2c5f5580365c69664eecb651f7e1b4065df7b..ca1542d5fdf88b7fa0e6e607ab019a98c5d2d770 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -53,8 +53,8 @@ bottom, it contains the following basic parameters:
 
        IO engine       How do we issue io? We could be memory mapping the
                        file, we could be using regular read/write, we
 
        IO engine       How do we issue io? We could be memory mapping the
                        file, we could be using regular read/write, we

-                       could be using splice, async io, syslet, or even
-                       SG (SCSI generic sg).
+                       could be using splice, async io, or even SG
+                       (SCSI generic sg).

 
        IO depth        If the io engine is async, how large a queuing
                        depth do we want to maintain?
 
        IO depth        If the io engine is async, how large a queuing
                        depth do we want to maintain?


@@ -329,18 +329,15 @@ directory=str     Prefix filenames with this directory. Used to place files
 filename=str   Fio normally makes up a filename based on the job name,
                thread number, and file number. If you want to share
                files between threads in a job or several jobs, specify
 filename=str   Fio normally makes up a filename based on the job name,
                thread number, and file number. If you want to share
                files between threads in a job or several jobs, specify

-               a filename for each of them to override the default. If
-               the ioengine used is 'net', the filename is the host, port,
-               and protocol to use in the format of =host,port,protocol.
-               See ioengine=net for more. If the ioengine is file based, you
-               can specify a number of files by separating the names with a
-               ':' colon. So if you wanted a job to open /dev/sda and /dev/sdb
-               as the two working files, you would use
-               filename=/dev/sda:/dev/sdb. On Windows, disk devices are
-               accessed as \\.\PhysicalDrive0 for the first device,
-               \\.\PhysicalDrive1 for the second etc. Note: Windows and
-               FreeBSD prevent write access to areas of the disk containing
-               in-use data (e.g. filesystems).
+               a filename for each of them to override the default.
+               If the ioengine is file based, you can specify a number of
+               files by separating the names with a ':' colon. So if you
+               wanted a job to open /dev/sda and /dev/sdb as the two working
+               files, you would use filename=/dev/sda:/dev/sdb. On Windows,
+               disk devices are accessed as \\.\PhysicalDrive0 for the first
+               device, \\.\PhysicalDrive1 for the second etc. Note: Windows
+               and FreeBSD prevent write access to areas of the disk
+               containing in-use data (e.g. filesystems).

                If the wanted filename does need to include a colon, then
                escape that with a '\' character. For instance, if the filename
                is "/dev/dsk/foo@3,0:c", then you would use
                If the wanted filename does need to include a colon, then
                escape that with a '\' character. For instance, if the filename
                is "/dev/dsk/foo@3,0:c", then you would use


@@ -374,6 +371,11 @@ filename_format=str
                default of $jobname.$jobnum.$filenum will be used if
                no other format specifier is given.
 
                default of $jobname.$jobnum.$filenum will be used if
                no other format specifier is given.
 

+unique_filename=bool   To avoid collisions between networked clients, fio
+               defaults to prefixing any generated filenames (with a directory
+               specified) with the source of the client connecting. To disable
+               this behavior, set this option to 0.
+

 opendir=str    Tell fio to recursively add any file it can find in this
                directory and down the file system tree.
 
 opendir=str    Tell fio to recursively add any file it can find in this
                directory and down the file system tree.
 


@@ -403,6 +405,7 @@ rw=str              Type of io pattern. Accepted values are:
                        trimwrite       Mixed trims and writes. Blocks will be
                                        trimmed first, then written to.
 
                        trimwrite       Mixed trims and writes. Blocks will be
                                        trimmed first, then written to.
 

+               Fio defaults to read if the option is not specified.

                For the mixed io types, the default is to split them 50/50.
                For certain types of io the result may still be skewed a bit,
                since the speed may be different. It is possible to specify
                For the mixed io types, the default is to split them 50/50.
                For certain types of io the result may still be skewed a bit,
                since the speed may be different. It is possible to specify


@@ -697,11 +700,14 @@ ioengine=str      Defines how the job issues io to the file. The following
                        sync    Basic read(2) or write(2) io. lseek(2) is
                                used to position the io location.
 
                        sync    Basic read(2) or write(2) io. lseek(2) is
                                used to position the io location.
 

-                       psync   Basic pread(2) or pwrite(2) io.
+                       psync   Basic pread(2) or pwrite(2) io. Default on all
+                               supported operating systems except for Windows.

 
                        vsync   Basic readv(2) or writev(2) IO.
 
 
                        vsync   Basic readv(2) or writev(2) IO.
 

-                       psyncv  Basic preadv(2) or pwritev(2) IO.
+                       pvsync  Basic preadv(2) or pwritev(2) IO.
+
+                       pvsync2 Basic preadv2(2) or pwritev2(2) IO.

 
                        libaio  Linux native asynchronous io. Note that Linux
                                may only support queued behaviour with
 
                        libaio  Linux native asynchronous io. Note that Linux
                                may only support queued behaviour with


@@ -713,6 +719,7 @@ ioengine=str        Defines how the job issues io to the file. The following
                        solarisaio Solaris native asynchronous io.
 
                        windowsaio Windows native asynchronous io.
                        solarisaio Solaris native asynchronous io.
 
                        windowsaio Windows native asynchronous io.

+                               Default on Windows.

 
                        mmap    File is memory mapped and data copied
                                to/from using memcpy(3).
 
                        mmap    File is memory mapped and data copied
                                to/from using memcpy(3).


@@ -721,9 +728,6 @@ ioengine=str        Defines how the job issues io to the file. The following
                                vmsplice(2) to transfer data from user
                                space to the kernel.
 
                                vmsplice(2) to transfer data from user
                                space to the kernel.
 

-                       syslet-rw Use the syslet system calls to make
-                               regular read/write async.
-

                        sg      SCSI generic sg v3 io. May either be
                                synchronous using the SG_IO ioctl, or if
                                the target is an sg character device
                        sg      SCSI generic sg v3 io. May either be
                                synchronous using the SG_IO ioctl, or if
                                the target is an sg character device


@@ -748,7 +752,7 @@ ioengine=str        Defines how the job issues io to the file. The following
 
                        cpuio   Doesn't transfer any data, but burns CPU
                                cycles according to the cpuload= and
 
                        cpuio   Doesn't transfer any data, but burns CPU
                                cycles according to the cpuload= and

-                               cpucycle= options. Setting cpuload=85
+                               cpuchunks= options. Setting cpuload=85

                                will cause that job to do nothing but burn
                                85% of the CPU. In case of SMP machines,
                                use numjobs=<no_of_cpu> to get desired CPU
                                will cause that job to do nothing but burn
                                85% of the CPU. In case of SMP machines,
                                use numjobs=<no_of_cpu> to get desired CPU


@@ -1063,7 +1067,8 @@ nice=int  Run the job with the given nice value. See man nice(2).
 
 prio=int       Set the io priority value of this job. Linux limits us to
                a positive value between 0 and 7, with 0 being the highest.
 
 prio=int       Set the io priority value of this job. Linux limits us to
                a positive value between 0 and 7, with 0 being the highest.

-               See man ionice(1).
+               See man ionice(1). Refer to an appropriate manpage for
+               other operating systems since meaning of priority may differ.

 
 prioclass=int  Set the io priority class. See man ionice(1).
 
 
 prioclass=int  Set the io priority class. See man ionice(1).
 


@@ -1219,6 +1224,7 @@ mem=str           Fio can use various types of memory as the io unit buffer.
                The allowed values are:
 
                        malloc  Use memory from malloc(3) as the buffers.
                The allowed values are:
 
                        malloc  Use memory from malloc(3) as the buffers.

+                               Default memory type.

 
                        shm     Use shared memory as the buffers. Allocated
                                through shmget(2).
 
                        shm     Use shared memory as the buffers. Allocated
                                through shmget(2).